评论系统代码阅读笔记

1.以获取主持人嘉宾等的留言为例：

$cacheKey = implode('_', array('cache_special', $fid, $lastid, $replyNum, $page, $limit, $withTop, $withAvatar));
    
$callback = array(
    'method'=> 'dataSpecial',
    'params'=>array($result, $fid, $lastid, $replyNum, $withTop, $withAvatar, $offset, $limit)
);

ResponseHelper::outputList( CacheHelper::run($cacheKey, $callback) );   

通过CacheHelper::run()方法处理缓存键、回调方法；  

2.判断缓存是否需要更新

$result = @ unserialize($result);
$update = $result['_expires'] < $nowTime;  
//调用缓存回调函数帮助类获取数据
$helper = new CacheCallbackHelper();
$result = $helper->{$callback['method']}($callback['params']);  

3.请求cacheCallbackHelper类

public function dataSpecial($params) {

    list($data, $total) = SearchHelper::getSpecial($fid, $lastid, SearchHelper::LESS, $offset, $limit);
    return $result;
}
//找到searchHelper::getSpecial方法  

4.请求SearchHelper::getSpecial方法

   public static function getSpecial($fid, $lastid = 0, $rule = self::LARGER, $offset = 0, $limit = 20) {
    $users = DataHelper::getSpecialUsers($fid);
    
    $criteria = new CDbCriteria;
    $criteria->select = self::SELECT;
    $criteria->compare('fid', $fid);
    $criteria->compare('invisible', 0);
    $criteria->compare('replyid', 0);
    $criteria->addInCondition('authorid', array_keys($users));
    
    $total = Comment::model($fid)->count($criteria);
    
    $data = Comment::model($fid)->findAll($criteria);
    
    return array($data, (int)$total);
}
//找到Comment::model()->findAll();  

5.请求Comment::model()方法

public static function model($shardingVal = null)
{
    CModelManager::addRule('Comment', 'pre_post_[\d]{1,2}');
    self::setShardedValue($shardingVal);
    return parent::model(__CLASS__); 
}  
//找到setShardedValue();方法  
//添加表名称到model的映射关系

6.请求CShardedActiveRecord的setShardedValue()方法

将fid当做分库分表值传给全局变量：$_shardedValue  

7.通过$_shardedValue选择对应的数据库 和数据表

private static function choose() {
    if(null === self::$_shardedValue) throw new CDbException('Sharded value is not set! Please call self::setShardedValue($value) first.');
    
    CDbManager::conn()->sharded(self::$_shardedValue);
    
    self::chooseDb();
    self::chooseTable();
}

8.请求CDbManager：：conn()->sharded()方法

public function sharded($value) {
    $shardedModel = CShardedMethod::model();
    

    //找到分库键值
    $this->_dbKey = $shardedModel->{$this->dbShardedMethod}($value);

    $this->_config = $this->connectionConfig[$this->_dbKey];
    //找到分表键值
    $this->_tableKey = $shardedModel->{$this->tableShardedMethod}($value);
    //对应 CShardedMethod 类中的 方法名
    
    return $this;
}

9.分库键值方法、分表键值方法CShardedMethod类

配置dbManager_v3文件中的属性：
   'dbShardedMethod'=> 'mod8',
   'tableShardedMethod'=> 'mod64',

public function mod8($number) {
    return $number % 8;
}

public function mod16($number) {
    return $number % 16;
}

public function mod64($number) {
    return $number % 64;
}

//用$fid跟8 或者  64 求莫